Acne is a multifactorial disease with alterations in sebum composition and output and androgen metabolism recognized as agents in its etiopathogenesis. We have conducted for the past several years a longitudinal prospective study of the development of acne as influenced by changes in detailed sebum composition, androgen excretion, bacterial flora of the skin, and pubertal stage in 60 children ages 7 through 11. We have identified changes in the character of sebum at puberty and in androgen excretion which may be critical in producing acne. We wish to continue to follow longitudinally changes in sebum composition, androgen levels and bacterial flora as correlated with pubertal staging, age and the appearance of comedos, papules, pustules and graded acnes in our study population. Determinations of correlations between these parameters and the clinical appearance of acne will identify more precise mechanisms in the pathogenesis of acne at its earliest stages and will help in focusing the search for potentially more effective prevention and early control therapeutic interventions. The other interrelated studies which we are performing include altering the hormonal environment of the sebaceous glands in order to change sebum output and composition identifying the function of acylated derivatives of testosterone and DHT found in sebaceous gland nuclei and determining the effect of 13-cis retinoic acid on the metabolism of human sebaceous glands.